I hope this does work, somebody please say if it does, i am an elderley gent and am finding it increasingley difficult to bend down to weed my lawn. If i could just stand and urinate on the weeds it would be so much easier. Although my neighbours may give me some funny looks!!!
Sadly not always. Some plants, such as moss, would be killed by the nitrogen levels, but nettles would thrive on it, thistles probably be ok, and daisies grow deformed leaves but cope. The grass might be killed off first, as it is not tolerant of high nitrogen. Use salt if the plants are on paths, or if on a lawn plunge a red hot skewer into them. (a soldering iron will do nicely. Or just get a proprietary weedkiller.